Sensor Output Control Feedback Loop for Signal Accuracy
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Solution Overview
Problem
Sensor integrated circuits face challenges in maintaining accurate output signal levels due to variations in pull up voltages and resistances, which can lead to faulty diagnostics and inadequate communication of sensor failures in safety-critical applications.
Innovation Solution
A digital output control feedback loop that dynamically compensates for a wide range of pull up voltages and resistances, allowing the sensor to adjust output signal levels and detect faults by switching between predetermined levels, enabling accurate diagnostics and customizable signal shaping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor uses a fixed output signal level without dynamic compensation, then the device complexity is reduced, but the output signal accuracy deteriorates due to variations in pull up voltages and resistances
Solution Approach 1:
The patent implements a feedback mechanism where the sensor monitors its own output signal level and dynamically adjusts compensation values to maintain accurate output despite variations in pull up voltages and resistances. The feedback loop compares the actual output signal with the expected signal and applies corrections to eliminate errors caused by load variations.
Solution Approach 2:
The sensor dynamically changes output signal parameters (voltage levels, current levels) based on detected load conditions. By measuring the actual pull up voltage and resistance values, the sensor adjusts its output parameters in real-time to compensate for variations and maintain signal accuracy across different operating conditions.
2Measurement precision
If the sensor implements dynamic compensation for pull up voltage and resistance variations, then the output signal accuracy is improved, but the ease of operation deteriorates due to increased configuration complexity
Solution Approach 1:
The sensor performs self-calibration and self-compensation by automatically measuring its own output signal characteristics and adjusting internal parameters without requiring external intervention. The device independently detects load variations and applies corrections, eliminating the need for manual configuration or calibration by the user.
Solution Approach 2:
The sensor performs preliminary measurement of pull up voltage and resistance values during initialization or calibration phases, storing these characteristics for use during normal operation. This preliminary action enables the sensor to pre-compute compensation values that simplify subsequent operation while maintaining accuracy.
3Reliability
If the sensor provides multiple output signal levels for diagnostics, then the reliability is improved through better fault detection, but the device complexity increases due to additional signal levels and control logic
Solution Approach 1:
The sensor's output driver is designed to universally handle multiple signal levels using the same hardware infrastructure. The controllable current sink can operate at different current levels to produce various output voltage levels, allowing the system to convey both normal measurement data and diagnostic fault information through a single output channel without requiring separate dedicated circuits for each function.
Data Source
AI summary
A sensor configured to generate a sensor output signal at a sensor output coupled to a pull up voltage through a pull up resistor includes a sensing element configured to generate a sensing element output signal indicative of a sensed parameter and a processor responsive to the sensing element output signal and configured to generate a processor output signal indicative of the sensed parameter. A digital output controller is responsive to the processor output signal and to a digital feedback signal and is configured to generate a controller output signal. An analog output driver is responsive to the controller output signal and configured to generate the sensor output signal at a first predetermined level or at a second predetermined level and a feedback circuit coupled between the sensor output and the digital output controller is configured to generate the digital feedback signal in response to the sensor output signal.